2002 Volvo S40 Alternator charging

2002 VOLVO S40
15,000 MILES • 4 CYL • 2WD • AUTOMATIC
Avatar
ZSELECPE
  • MEMBER
  • 1 POST
How long does a car need to be run (or engine to be idling) to re-charge a battery which has gone mostly dead but has been jumped successfully? Thank You, Pete z.
Aug 25, 2009 at 9:07 PM
Advertisement
Avatar
MHPAUTOS
  • ✓ASE Certified Mechanic
  • 31,937 POSTS
  • ASE Certified Mechanic
Hi there,

With the car idling you will only get what is called a surface charge, this is not enough to normally get the car going if you turn it off, at least take it for a long drive so the alternator can charge at peak volts, remember that the alternator is not designed to fully deep cycle charge a battery from a fully flat stat, it is designed to keep the battery topped up while demand is placed on it from all the systems that it feeds.

mark (mhpautos)
Aug 25, 2009 at 9:13 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.